The Box of Jhana was a powerful Kinda healing device. It was capable of repairing severe mood disorders such as nervous breakdowns. It could also be used to deliver psychic messages. It was apparently intended primarily for use on females, as males exposed to it regressed to a childlike mental state. However, the Fifth Doctor was unaffected; either due to being a Time Lord, more evolved humanoid, or because he already possessed a kind nature.
The Doctor speculated that it operated on a sonic level outside of normal hearing range, bringing the mind into harmony with the natural world. As a side effect, it often disrupted electrical circuits. (TV: Kinda)